Protective device and the manufacture thereof



Oct. 12, 1948. w. w. wATRous, JR

PROTECTIVE DEVICE AND THE MANUFAGTURE THEREOF 2 Sheets-Sheet 1 Filedoet. 1e, 1942 Z INVENTOR M M awww/5, we. BY W Mmm/1 ATTORNEY Oct. 12,1948. w. w. wATRoUs, .JR

PROTECTIVE DEVICE AND THE MANUFACTURE THEREOF Filed oct. 1e, 1942 2Sheets-Sheet 2 Elf/flair mn/M15 INVENTOR WHT/E005) Je.

ATTORNEY Patented Oct. 12, 1948 PROTECTIVE DEVICE AND THE MANU- FACTURETHEREOF Ward W. Watrous, Jr., Chatham, N. J., assignor to WestinghouseElectric Corporation, East Pittsburgh, Pa., a corporation ofPennsylvania Application October 16, 1942, Serial No. 462,258

9 Claims.

This invention relates to automatic switches used as protective devicesin connection with high frequency transmission and reception.

The principal object of my invention, generally considered, is toprovide an automatic radial-type spark gap switch of extreme accuracy,insofar as the spacing of the electrodes is concerned, and a method ofmanufacturing such a device.

Another object of my invention is to provide a protective device forelectricity of high frequency, comprising a pair of electrodes,gas-tight means enclosing said electrodes, a tube which initially fitswithin one and receives the other of said electrodes, and means forwithdrawing said tube to leave a spark-gap space of the desired distanceand character between said electrodes.

A further object of my invention is the provision of a method ofaccurately positioning electrodes in a discharge device comprisingfitting a tube within one of said electrodes, fitting the otherelectrode within said tube, and withdrawing said tube to leave saidelectrodes spaced a desired distance.

Other objects and advantages of the invention, relating to theparticular arrangement and construction of the various parts, willbecome apparent as the description proceeds.

Referring to the drawings- Fig. 1 is an axial sectional view, with partsin elevation, of a protective device embodying my invention.

Fig. 2 is a transverse sectional View on the line II-II of Fig. l, inthe direction of the arrows.

Fig. 3 is an axial sectional view, with parts in elevation, showingparts of a device embodying my invention during the course ofmanufacture, on a somewhat larger scale than that of Figs. 1 and 2.

Fig. 4 is a View corresponding to Fig. 3 but illustrating a furtherstage in the manufacture of devices embodying my invention.

Fig. 5 is a view corresponding to Fig. 4 but showing the device justprior to sealing off.

Fig. 6 is a fragmentary view corresponding to Fig. 5 but showing anotherembodiment of my invention.

Fig. 7 is a sectional View, with parts in elevation, of a modified formof spacing tube.

Fig. 8 is a view corresponding to Fig. 7 but showing a furthermodification of the spacing tube.

The present application discloses a protector tube which is consideredan improvement over that described and claimed in my Patent No.

2. 2,288,861, dated July 7, 1942, and particularly the embodiments inwhich a radial discharge, as distinguished from one axial of theelectrodes, is provided for. Tests have indicated superiority ofoperation when a radial-type spark gap is used for sparking duringtransmission to keep the relatively-high sending energy from thereceiving apparatus, while not interfering with reception, in connectionwith such equipment as that used for locating aircraft. By radial-typegap, I mean one in which the major discharge occurs between a convex anda concave surface, usually in cylindrical form.

Such a gap is very difficult to properly manufacture, as it is extremelyhard to accurately align one electrode within the other. Eccentricalignment results in concentration of the discharge and increasedelectrostatic capacity, both of which may seriously affect operation. Inextreme cases of mis-alignment, the electrode surfaces may actuallytouch, thus shorting out the gap and rendering it worthless. If such agap has been made, it is very difcult to measure the spacing inaccordance with preceding practice. There has been some thought ofreducing the electrode spacing to the order of .0l inch. Such a smallspace requires accuracy well above that achievable by prior technique.In accordance with the present invention, I am able to accurately obtainnot only radial spacing' but also longitudinal spacing. In a preferredform, the invention involves a movable tube which can conveniently be anexhaust tube, located in such a manner that it acts as a spacer andguide during the glassing operation, but can be withdrawn from thedischarge region after such an operation. The tube may be withdrawnentirely after the glassing operation, or preferably soldered in a Xedlocation and used for exhaust purposes.

Referring to the drawings in detail, like parts being designated by likereference characters, and rst considering the embodiment of my inventionillustrated in Figs. 1 and 2, there is shown a protector tube IIcomprising a glass envelope I2, hollow cylindrical in form and with itsends closed by caps I3 and I4, desirably formed of Kovar or othersuitable material sealed to the glass. Kovar is an alloy containing 28.7to 29.2% nickel, 17.3 to 17.8% cobalt, 52.9 to 53.4% iron, not more than.06% carbon, not more than .5% manganese, and not more than .2% silicon.If Kovar is used, I prefer to employ glass, Corning #704, which is asoft borosilicate glass.

The cap I3 carries a terminal I5 which may ceiving a movable tube 2Iwhich maybe formed' of steel and adapted for exhausting purposes. Thistube has a normal outside diameter cor-- responding with a minimuminternal diameter of the female electrode I8, and a wall thicknesscorresponding with the desired radial spacing ofsaid electrode withrespect to a male electrode.V The male electrode 22 is also desirablyformed of aluminum and carried by the cap Ill, as by having a reducedthreaded extension 23 tting the correspondingly threaded terminal 24thereon,V`

said terminal being desirably welded, soldered, or both, to said cap asindicated at 25.

In order to limit relative movement between the combined spacing andexhaust tube 2I and '-the electrode Iii, :said exhaust tube has a stopportion 26, which may be formed byL upsetting an intermediate portionthereof, and which permits longitudinal movement of said tube only fromthe position shown in Fig. l, where it abu'ts the terminal i5, to thatshown in Fig. 3 where lit abuts ashoulder 2? provided by an interiorannular bossZii on the female electrode I8. It will, therefore, be seenthat movementY of the spacing tube 2i is from the initial or spacingposition, shown in Fig. 3,`to that shown in Fig. 1 where .it leaves adesired space between the electrodes.

Referring new to Fig. 3 which illustrates parts of th-e device in apreliminary stage of manufacture, the hollow cylindrical glass 'tube orenvelope portion l2 is heldin lathe jaws 29 while the terminal portionI5 is held in `cooperating, lathe jaws 3i, so that both the glassenvelope portion I2 and the terminal member i5 with its assembled capi3, lfen-'rale electrode I8 and spac' ine vtube 2i may be rotated at thesame speed,

heated by iires 32, gradually brought together,v

and sealed as indicatedat 33.

With fthe spacing tube i in the extrem-e inner position, asY eiected byengagement of a stop 313) therewith as shown in Fig. 4, and with'the'jaws 3|V still holding the termin-al I5 and its associated parts,now including the glass envelope portion I2, lthe terminal 2li and itsassociated cap I4` and male electrode 22 are vheld inV lathe jaws 29andV rotated at the same speed, heated by res- 32y and the partsgradually brought vtogether ,until the cap Iii is sealed to the other orright handvend of the glass envelope portion I2, the reduced? end oreffective portion 3l of the male electrode V2`2 Ifitting the tube 2!which controls the desired spacing between it and the female electrodeI8. The longitudinall spacing is controlledv by the length of thespacing `tube beyond .the-'stopo'r enlarged portion 25, while .theradial spacingis controlled Yby the wall thickness of said tube; the fitbetween the associated parts being snug and the wall thickness beingIaccurate so'that extreme accuracy in positioning the electrodesV may beeffected. Y l

Figf shows the alignment of theV parts ofthe protector tube after bothcaps have beenlsealed tothe envelope` I2 and lthe spacing tube 2| with-Y drawn to 'its extreme outer position wherefgitsl stop portion 25engages VtheYtern'iinaljr'nerr'lber I5, 75

whereupon the desired space, both radial and axial, is left between theadjacent or effective 4portions of the associated electrodes. The deviceis made air-tight, as by soldering 'the mov, Y

` ing the portion beyond the weld. L f

In Fig. 6 Ihave shown the modied portion-s of an alternative 'form ofprotector tube IIa in which ithe cap 13e carries a termin-al *I5asecured thereto as indicated at IBS, as in .the preceding embodiment.The inner threaded portion I'Ia .of the terminal also carries la femaleelectrode Illa, which is formed somewhat diierent from 'the electrode I8of the preceding Vembo-dimentLin that. the eiTective shoulder Y2Ia facestoward the male electrode 22a rather than 'away from it and serves tolimit inward rather than outwardmoveA ment of -the'tube 2 la. Themovable exhaus-t'tube 2|Var is of smaller relative diameter thanY tube21| of the preceding embodiment and carries an auxjiliary spacing oralignment tip All',V whi-ch may be formed of aluminum or'rnickel, havinga pocketk d5" fitting a correspondingly threaded portion 4=`I Y of thefemale electrodeY ie andV suitably secured as by. welding or forced tonY lthe movable tubel 2 Ia so'rth-at it may beturnedA to spacingposition, or un'til the shoulderY 26a thereon engag-esfthe 'terminalI5e, as in Figs. 3 and 44 in connection with the ,preceding embodiment.VInV suchfpos'iV` tion the male electrode22e`is nested with the tip Mvduring manufacture.- After assembly, the

extreme outward position, corresponding with the showing in Fig 5, whereit-engag'es. the terminal I'5, leaving the associated electrodes Illa'anid"22e in the desired.accur-ately-'spacedA position", corre'- spondingwith 'the showing o'f Figs: l? and 2, the

thickness of the tip wall which` dein'es thepocket i5 determiningthe-radial, andthe movement ofV said tip determining'the axialelectrodespaoing'.'

The deviceY may then be nished asf described in connection with* thepreceding ernbodimerit;V

Fig. 7. shows; a spacing tip Mb which is notintegral with the movableexhaust tube ZIlfbut rather securedtheretoV Yas byrwel'dir'i'g"Y orvforced t, said spacing tip having an opening'll'- com# municating withlsaid tube 'and an outstandingperipheral hollow cylindrical flange 49,the radial thickness of which corresponds with the vd'e'fsired radialspacing betweenV the associa-ted electrodes,

as in the-preceding embodiment. will'beudertive to the tip de `or thepreceding embodiment and alltheA parts not illustrated may" correspondwith .those of one offthe-precedingembodiments.

Fig- 8 illustrates an alternate Vspacing tube- 2Ic in which thel stopyorshoulder porti-on thereof, instead of being'formedlby' upsetting,comprises an annular ring 26C fitted thereto `and securediin`Y positionas by means of solder 5I. In this-cnnV bodiment the parts not shown maycorrespond f with those of any ofiheY preceding embodiment disclosed animproved form of protector tube, as well as an improved method ofassembling the parts, whereby accurate spacing between the electrodes,both radial and longitudinal, may be conveniently effected.

Although preferred embodiments of my invention have been disclosed, itwill be understood that modifications may be made within the spirit andscope of the appended claims.

I claim;

1. The method of positioning electrodes in a discharge device comprisingclosely tting a spacing tube of limited longitudinal movement within oneof said electrodes, closely fitting the other electrode within saidtube, while said spacing tube is positioned with respect to said oneelectrode nearest said other electr-ode, and withdrawing said tube fromsaid other electrode to the opposite extreme position of limitedmovement, leaving said electrodes spaced apart the desired distance.

2. The method of positioning electrodes in a discharge device comprisingsealing one of said electrodes in place with respect to an envelope,closely fitting a spacing tube of limited longitudinal movement withinsaid electrode, closely nesting the other electrode in said tube whenthe latter is in its extreme inward position, sealing said otherelectrode in place with respect to said envelope, and withdrawing saidtube from said other electrode to its outermost fixed position, wherebythe innermost position of said tube determines the longitudinal spacingof the electrodes and the wall thickness of the electrode-receivingportion of said tube determines the radial spacing.

3. The method of positioning a male electrode with respect to a femaleelectrode in a discharge device, comprising tting a movable exhaust tubewithin said female electrode, sealing said female electrode within anenvelope fitting the male electrode within said exhaust tube when thelatter is in innermost position, sealing said male electrode within saidenvelope, and withdrawing said exhaust tube to outermost xed positionleaving the desired space between said electrodes.

4. A discharge device comprising an electrode with an axial cylindricalaperture, another electrode with a cylindrical portion projecting intosaid aperture and coaxial therewith, an envelope for said device andenclosing said electrodes, and a combination spacing and exhaust tube,coaxial with said electrodes, whose outer diameter is substantiallyequal to the diameter of the electrode aperture and whose inner diameteris substantially equal to the diameter of the projecting portion of saidother electrode, whereby it serves to accurately position saidelectrodes both axially and radially during manufacture, and iswithdrawn to the outermost position and sealed with respect to saidenvelope after said positioning operation.

5. A protective device for electricity of high frequency comprising apair of electrodes, means enclosing said electrodes, and a spacing tubewhich initially fits within one and receives the other of saidelectrodes, said tube being initially withdrawable to an outer positionleaving a spark-gap space, and means sealing said tube in said outerposition leaving a spark-gap of the desired distance between saidelectrodes.

6. A protective device for electricity of high frequency comprising afemale electrode, a spacing tube therein and initially longitudinallymovable with respect thereto, a male electrode tting the inner end ofsaid spacing tube, means enclosing said electrodes, and means sealingsaid spacing tube in extreme outermost position with respect to saidfemale electrode, whereby a sparkgap space of the desired distance andcharacter between said electrodes is produced.

7. A protective device for electricity of high frequency comprising afemale electrode, a spacing tube longitudinally slidable with respectthereto, a male electrode snugly nestable with the inner end of saidspacing tube, a cap carrying each electr-ode, a glass envelope portioncovering the space between said caps, said tube having shoulder meansfor limiting its movement, and means sealing said spacing tube withrespect to said female electrode leaving a gap between said electrodesof the desired distance and character.

8. A protective device for electricity of high frequency comprising afemale electrode, an exhaust tube longitudinally sliadable with respectthereto, a spacing tip carried by the inner end portion of said tube, amale electr-ode snugly nestable with the inner end of said tip, a capcarrying each electrode, a glass envelope portion covering the spacebetween said caps, said tube having shoulder means for limiting itsmovement, said tip being threaded into said female electrode, and meanssealing said spacing tube with respect to said female electrode leavinga gap between said electrodes of the desired distance and character.

9. A protective device for electricity of high frequency comprising afemale electrode, an eX- haust tube longitudinally slidable with respectthereto, a spacing tip carried by the inner end portion of said tube, amale electrode snugly nestable with the inner end of said tip, a capcarrying each electrode, a glass envelope portion covering the spacebetween said caps, said tube having shoulder means for limiting itsmovement, and means sealing said spacing tube with respect to saidfemale electrode leaving a gap between said electrodes of the desireddistance and character.

WARD W. WATROUS, JR.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Number Name Date 1,656,956 Schroter Jan. 24, 19281,930,088 Foulke Oct. 10, 1933 2,174,853 Bowie Oct. 3, 1939 2,225,465Scharfnagel Dec. 17, 1940 2,272,882 Brown Feb. 10, 1942 2,320,941 LittonJune 1, 1943 2,397,982 Salzberg Apr. 9, 1946 2,422,324 Watrous, Jr. June17, 1947

